1989368640 has 672 divisors, whose sum is σ = 8450519040. Its totient is φ = 438939648.

The previous prime is 1989368639. The next prime is 1989368657. The reversal of 1989368640 is 468639891.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15664257 + ... + 15664383.

Almost surely, 2^1989368640 is an apocalyptic number.

1989368640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1989368640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4225259520).

1989368640 is an abundant number, since it is smaller than the sum of its proper divisors (6461150400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1989368640 is a wasteful number, since it uses less digits than its factorization.

1989368640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 181 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 54.

The square root of 1989368640 is about 44602.3389521222. The cubic root of 1989368640 is about 1257.6846368071.

The spelling of 1989368640 in words is "one billion, nine hundred eighty-nine million, three hundred sixty-eight thousand, six hundred forty".